Phosphate Molecular Tweezers Constructed From Internal Sites Within One‐Dimensional Covalent Organic Frameworks for High‐Precision Uranium‐Capturing

ABSTRACT Integrating uranium‐specific binding moieties into materials represents a pivotal yet challenging strategy for environmental uranium extraction, essential for advancing sustainable nuclear energy and environmental remediation. Herein, we discover that the precise installation of molecular tweezers within the pores of 1D covalent organic frameworks, leveraging the flexibility of the chains, enables dynamic and highly selective uranium capture. Using 2‐OH‐PyDFP as the scaffold, 2‐Phos is synthesized through phosphorylation of the hydroxyl groups lining the interior channel. The symmetrically distributed phosphate moieties enable synergistic function as molecular tweezers, endowing the material with exceptional selectivity and adsorption performance. Remarkably, 2‐Phos achieves a uranium adsorption capacity of 954 mg·g −1 at pH = 8, representing an approximately 63% enhancement over the control material 5‐Phos, whose phosphate groups are located externally to the pores. Density functional theory calculations further revealed that upon interacting with uranium, the distance between the ends of the molecular tweezers shrink from 13.0 to 11.0 Å owing to the self‐contraction of the chains. Such sub‐nanometer‐scale structural adjustment, combined with size confinement and multi‐site cooperative chelation, collectively enhances the efficient adsorption of uranium. This study proposes a strategy based on constructing size‐matched nanotraps within the porous architecture to achieve highly efficient adsorption of specific molecules.